Show me the evidence to guide nutrition practice: Scoping review of macronutrient dietary treatments after metabolic and bariatric surgery

Background: Clinical practice recommendations for macronutrient intake in Metabolic and Bariatric Surgery (MBS) are insufficiently grounded in the research, possibly due to a paucity of research in key areas necessary to support macronutrient recommendations. An initial scoping review, prior to any systematic review, was determined to be vital. Objectives: To identify topical areas in macronutrients and MBS with a sufficient evidence base to guide nutrition recommendations. Methods: PubMed, Cochrane, Ovid Medline, and Embase were initially searched in January 2019 (updated November 1, 2023) with terms encompassing current bariatric surgeries and macronutrients. Out of 757 records identified, 98 were included. A template was created. Five types of outcomes were identified for extraction: dietary intake, anthropometrics, adverse symptoms, health, and metabolic outcomes. All stages of screening and extraction were conducted independently by at least two authors and disagreements were resolved via team discussion. Macronutrient-related dietary treatments were classified as either innovative or standard of care. Descriptions of dietary arms were extracted in detail for a qualitatively generated typology of dietary or nutritional treatments. Heatmaps (treatments by outcomes) were produced to identify promising topics for further systematic analyses. Results: We identified protein supplementation and “food-focused” (e.g., portion-controlled meals, particular foods in the diet, etc.) topical areas in MBS nutrition care with potentially sufficient evidence to create specific MBS Macronutrients guidelines and identified topical areas with little research. Conclusions: Clinical practice regarding macronutrient intake remains guided by consensus and indirect evidence. We detail ways that leadership at the profession level may remedy this.